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authorHalil Pasic <pasic@linux.vnet.ibm.com>2017-01-30 05:09:36 -0500
committerMichael S. Tsirkin <mst@redhat.com>2017-02-03 16:38:57 -0500
commitcda8bba0f99d25d2061c531113c14fa41effc3ae (patch)
treea8efcd70106ad7dc0fb3b56bd1a0ccb79b757d26
parent0d5415b489f68b58e1983a53793d25d53098ed4b (diff)
vhost: fix initialization for vq->is_le
Currently, under certain circumstances vhost_init_is_le does just a part of the initialization job, and depends on vhost_reset_is_le being called too. For this reason vhost_vq_init_access used to call vhost_reset_is_le when vq->private_data is NULL. This is not only counter intuitive, but also real a problem because it breaks vhost_net. The bug was introduced to vhost_net with commit 2751c9882b94 ("vhost: cross-endian support for legacy devices"). The symptom is corruption of the vq's used.idx field (virtio) after VHOST_NET_SET_BACKEND was issued as a part of the vhost shutdown on a vq with pending descriptors. Let us make sure the outcome of vhost_init_is_le never depend on the state it is actually supposed to initialize, and fix virtio_net by removing the reset from vhost_vq_init_access. With the above, there is no reason for vhost_reset_is_le to do just half of the job. Let us make vhost_reset_is_le reinitialize is_le. Signed-off-by: Halil Pasic <pasic@linux.vnet.ibm.com> Reported-by: Michael A. Tebolt <miket@us.ibm.com> Reported-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Fixes: commit 2751c9882b94 ("vhost: cross-endian support for legacy devices") Cc: <stable@vger.kernel.org> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Greg Kurz <groug@kaod.org> Tested-by: Michael A. Tebolt <miket@us.ibm.com>
-rw-r--r--drivers/vhost/vhost.c10
1 files changed, 4 insertions, 6 deletions
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index d6432603880c..8f99fe08de02 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -130,14 +130,14 @@ static long vhost_get_vring_endian(struct vhost_virtqueue *vq, u32 idx,
130 130
131static void vhost_init_is_le(struct vhost_virtqueue *vq) 131static void vhost_init_is_le(struct vhost_virtqueue *vq)
132{ 132{
133 if (vhost_has_feature(vq, VIRTIO_F_VERSION_1)) 133 vq->is_le = vhost_has_feature(vq, VIRTIO_F_VERSION_1)
134 vq->is_le = true; 134 || virtio_legacy_is_little_endian();
135} 135}
136#endif /* CONFIG_VHOST_CROSS_ENDIAN_LEGACY */ 136#endif /* CONFIG_VHOST_CROSS_ENDIAN_LEGACY */
137 137
138static void vhost_reset_is_le(struct vhost_virtqueue *vq) 138static void vhost_reset_is_le(struct vhost_virtqueue *vq)
139{ 139{
140 vq->is_le = virtio_legacy_is_little_endian(); 140 vhost_init_is_le(vq);
141} 141}
142 142
143struct vhost_flush_struct { 143struct vhost_flush_struct {
@@ -1714,10 +1714,8 @@ int vhost_vq_init_access(struct vhost_virtqueue *vq)
1714 int r; 1714 int r;
1715 bool is_le = vq->is_le; 1715 bool is_le = vq->is_le;
1716 1716
1717 if (!vq->private_data) { 1717 if (!vq->private_data)
1718 vhost_reset_is_le(vq);
1719 return 0; 1718 return 0;
1720 }
1721 1719
1722 vhost_init_is_le(vq); 1720 vhost_init_is_le(vq);
1723 1721